Use of extracorporeal life support for adult patients with respiratory failure and sepsis

A Systematic Review of Preexisting Sepsis and Extracorporeal Membrane Oxygenation

We retrospectively reviewed all pertinent extracorporeal membrane oxygenation (ECMO) studies (January 1995 to September 2017) of adults with sepsis as a primary indication for intervention and its association with morbidity and mortality. Collected data included study type, ECMO configuration, outcomes, effect size, and other features. Advanced age was a risk factor for death. Compared with nonsurvivors, survivors had a lower median Sepsis-Related Organ Failure Assessment score on day 3 (15 vs. 18, p = 0.01). Biomarkers in survivors and nonsurvivors, respectively, were peak lactate (from two studies: 4.5 vs. 15.1 mmol/L, p = 0.03; 3.6 ± 3.7 vs. 3.3 ± 2.4 mmol/L, p = 0.850) and procalcitonin levels (41 vs. 164 ng/ml, p = 0.008). Bacteremia was associated with catheter colonization, and 90.5% of a group without bloodstream infections survived to discharge; ECMO weaning was possible for less than half the bloodstream infection group. Myocarditis portended favorable outcomes for patients with sepsis who received ECMO. Extracorporeal membrane oxygenation was used in immunosuppressed patients with refractory cardiopulmonary insufficiency from severe sepsis with successful weaning from ECMO for most patients. Overall survival varied substantially among studies (15.38-71.43%). Existing studies do not present well-defined patterns supporting use of ECMO in sepsis because of sample sizes and disparate study designs.

Extracorporeal Membrane Oxygenation for Adults With Refractory Septic Shock

Because of a severe dysregulation of the host response to infection, septic shock may induce a profound imbalance between oxygen consumption and delivery, which in some cases may be refractory to conventional support measures. In this setting, extracorporeal membrane oxygenation (ECMO) may help to restore this ratio. Indeed, in neonates and children, this technique is already established as a valid salvage therapy. In spite of the rapid growth in the use of ECMO in recent years, the evidence of its benefits in adult patients is weak, particularly in cases of refractory septic shock. Nevertheless, several case series have reported good outcomes in selected cases with specific management. Here we explore the links between sepsis and ECMO, starting with the basic biology underlying the two entities. We then review the published literature on the use of extracorporeal support in adult patients with septic shock and finally conclude with a review of the key points of management that can optimize the results after this critical situation.

Outcomes of Adult Patients With Septic Shock Undergoing Extracorporeal Membrane Oxygenation Therapy

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been shown to provide benefits in children, but not adults, with septic shock. This study described the clinical outcomes of adults in septic shock who underwent ECMO.

METHODS

This study retrospectively investigated adults who were supported on venoarterial or venovenous modes of ECMO and who had septic shock at the time of cannulation from January 1, 2009 to December 31, 2016 at a quaternary medical center in the United States. The primary outcomes were rate of survival to hospital discharge and time to survival using Kaplan-Meier survival estimates. This study analyzed survival by mode, previous cardiac arrest, and timing of cannulation (<96 and ≥96 hours after admission to the intensive care unit). Secondary outcomes were complications and days of ECMO support, length of stay in the intensive care unit, and hospitalization days.

RESULTS

Of 243 patients supported on ECMO during this 7-year period, 32 met the criteria for septic shock, and the majority had a pulmonary source of infection (72%). The most common mode of support was venovenous ECMO (65%), and median ejection fraction was 51%. Median time on ECMO was 5.8 days (interquartile range, 2.6, 11.3 days). Survival to hospital discharge was 13 of 32 (41%), whereas median survival was 14.5 days (interquartile range, 5.2, 23.7 days). There was no statistically significant difference in survival by subgroup, including ECMO mode. Health care-associated infections were frequent (25%).

CONCLUSIONS

This cohort of patients undergoing ECMO had equivalent median survival compared with literature-based estimates of other cohorts of patients with septic shock.

Successful Use of Extracorporeal Membrane Oxygenation in an Adult Patient With Toxic Shock-Induced Heart Failure

Cardiomyopathy secondary to toxic shock syndrome (TSS) is an uncommon but potentially life-threatening problem. We report the case of a 51-year-old male who presented with profound cardiogenic shock and multiorgan failure that could not be managed by conventional therapy with intravenous fluids, vasopressors and inotropes. Venoarterial extracorporeal membrane oxygenation (VA ECMO) was instituted as a bridge to recovery. After administration of antibiotics and intravenous immunoglobulin, the patient’s condition improved and he was successfully weaned off ECMO after 6 days. The patient recovered from multiorgan failure, and left ventricular ejection fraction improved from <10% pre-ECMO to 65% 8 months after discharge. This case supports the view that VA ECMO can be used successfully to support vital organ perfusion in patients with profound but reversible cardiomyopathy attributed to TSS.

A review of the fundamental principles and evidence base in the use of extracorporeal membrane oxygenation (ECMO) in critically ill adult patients

Extracorporeal membrane oxygenation (ECMO) comprises a commonly used method of extracorporeal life support. It has proven efficacy and is an accepted modality of care for isolated respiratory or cardiopulmonary failure in neonatal and pediatric populations. In adults, there are conflicting studies regarding its benefit, but it is possible that ECMO may be beneficial in certain adult populations beyond postcardiotomy heart failure. As such, all intensivists should be familiar with the evidence-base and principles of ECMO in adult population. The purpose of this article is to review the evidence and to describe the fundamental steps in initiating, adjusting, troubleshooting, and terminating ECMO so as to familiarize the intensivist with this modality.

Prolonged venovenous extracorporeal membrane oxygenation in a child with leukemia and persistent bacteremia

OBJECTIVE

In patients who require extracorporeal membrane oxygenation for prolonged periods, it is uncertain whether nosocomial bacteremia that persists throughout an entire extracorporeal membrane oxygenation run can be associated with good outcomes.

DESIGN

Case report.

SETTING

Tertiary pediatric intensive care unit.

PATIENT

A 6-yr-old boy with acute myeloid leukemia and prolonged mechanical ventilatory support.

INTERVENTIONS

Venovenous extracorporeal membrane oxygenation.

MEASUREMENTS AND MAIN RESULTS

The patient required extracorporeal membrane oxygenation for refractory hypoxia secondary to nosocomial pneumonia. On day 2 of the extracorporeal membrane oxygenation run and every day thereafter, blood cultures were consistently positive for Stenotrophomonas maltophilia despite combination therapy with intravenous polymyxin B and cotrimoxazole. Excluding the cannulae, the extracorporeal membrane oxygenation circuit was electively changed once during the run but without any effect on bacteremia. After 38 days of extracorporeal membrane oxygenation, the patient was successfully decannulated and the bacteremia ceased. He remains completely well and disease-free at 6-month follow-up.

CONCLUSIONS

Sustained bacteremia during an extracorporeal membrane oxygenation run should not be regarded as a reason to withdraw extracorporeal support, although efforts are clearly warranted to identify possible sources of sepsis and wean off extracorporeal membrane oxygenation at the earliest opportunity.

The Role of Extra Corporeal Membrane Oxygenation for Treatment of the Adult Respiratory Distress Syndrome: Review and Quantitative Analysis

The role of Extra corporeal membrane oxygenation (ECMO) has not been formally validated for patients with adult respiratory distress syndrome. In anticipation of publication of the conventional ventilation versus ECMO in severe adult respiratory failure (CESAR) trial, the role of ECMO in this setting was reviewed.

An electronic search for studies reporting the use of ECMO for the treatment of adult respiratory distress syndrome revealed two randomised controlled trials and three non-controlled trials. Bayesian analysis on the two randomised controlled trials produced an odds ratio mortality of 1.28 (credible interval 0.24 to 6.55) demonstrating no significant harm or benefit. Pooling was not possible for the non-controlled studies because of differing admission status and ECMO selection criteria and an inability to control for these differences in the absence of individual patient data. A large number (n=35) of case series have been published with generally more positive results. We also present a comprehensive narrative commentary on the history, current practice and future for ECMO.

ECMO, as rescue therapy for adult respiratory distress syndrome, appears to be an unvalidated rescue treatment option. Analysis and review of trial data does not support its application; however the body of reported cases suggests otherwise. Until the CESAR trial provides an authoritative answer ECMO will continue to be offered on a case by case basis.

Extracorporeal membrane oxygenation for refractory septic shock in children: one institution's experience

OBJECTIVE

To report our institutional experience of venoarterial extracorporeal membrane oxygenation (ECMO) in children with septic shock and circulatory collapse.

DESIGN

Retrospective case series.

SETTING

Intensive care unit of a tertiary pediatric referral center.

PATIENTS

Forty-five children with refractory septic shock who received venoarterial ECMO for hemodynamic support.

INTERVENTIONS

Venoarterial ECMO.

MEASUREMENTS AND MAIN RESULTS

We measured mean arterial pressure and inotropes before cannulation, ventilator settings, oxygenation, site and cause of infection, time on ECMO, complications of ECMO relating to the circuit or anticoagulation, survival to hospital discharge, and functional outcome assessment. Between July 1988 and October 2006, 441 children at our institution received extracorporeal life support for a variety of indications. Forty-five (10%) with septic shock received venoarterial ECMO specifically for hemodynamic support. Eighteen (40%) of these had suffered cardiac arrest and were receiving chest compressions immediately before cannulation. The median time spent on ECMO was 84 hrs (range, 32-135). There were mechanical problems with the ECMO circuit requiring intervention in 17 (38%) patients, such as oxygenator or pump head failure, clots in the circuit, or cannulae malposition. This caused no long-term harm in any but one of the patients, who died during a circuit change. Eleven patients (24%) had clinically apparent episodes of bleeding that required surgical intervention or blood transfusion. Twenty-one (47%) patients survived to hospital discharge. Atrioaortic cannulation through a sternotomy incision was associated with an improvement in survival to hospital discharge (73% of those with central cannulation survived vs. 44% without, p = .05). No survivors had severe disability at long-term follow-up.

CONCLUSIONS

Extracorporeal membrane oxygenation can be safely used to resuscitate and support children with sepsis and refractory shock. Sepsis and multiorgan failure should not be considered a contraindication to ECMO. This study adds support to existing guidelines.

Extracorporeal life support for severe adult respiratory failure

PURPOSE OF REVIEW

The past 35 years have provided a wealth of evidence that mechanical ventilation, although potentially life saving, can injure the lungs. Recent evidence suggests that limiting ventilating gas volumes can reduce patient mortality, but may result in progressive parenchymal derecruitment and alveolar hypoventilation, potentially aggravating systemic hypercarbia and hypoxemia. This review summarizes the current recommendations on a controversial, invasive technique termed 'extracorporeal life support' as a means to provide temporary pulmonary support during 'lung-protective' strategies.

RECENT FINDINGS

Extracorporeal life support has been implemented since the origins of cardiopulmonary bypass in the 1950s, but differs in several important ways from cardiopulmonary bypass, including its prolonged duration of application. Because extracorporeal life support serves only to supplement physiological derangements and is not therapeutic, patient selection critically impacts results. Whereas reversible neonatal processes such as meconium aspiration and persistent fetal circulation have fostered clinical trials demonstrating the efficacy of extracorporeal life support, adult cardiopulmonary failure extracorporeal life support trials have proved less compelling. Despite two prospective randomized trials that failed to demonstrate its efficacy, adult extracorporeal life support continues in limited centers of excellence. Adult extracorporeal life support survival rates for respiratory failure average 50% when strict criteria are met, but it remains unclear whether these results represent improved outcomes.

SUMMARY

Extracorporeal life support is an invasive technique that can provide support to the failing lung. Clinical trials have demonstrated its efficacy in neonatal and pediatric patients, but data in adults are less clear. An ongoing trial in the UK will soon address this important issue.

Peritoneal perfusion with oxygenated perfluorocarbon augments systemic oxygenation

Background

Despite maximal ventilatory support, many patients die from hypoxia in the setting of potentially reversible pulmonary failure. There remains a pressing need for additional pulmonary supportive care measures, especially techniques that do not require systemic anticoagulation. The objective of our experiments was to determine whether systemic oxygenation could be increased in a large animal, with induced hypoxia, by perfusing the abdominal cavity with oxygenated perfluorocarbons.

Methods

Fifteen pigs with a mean (± SD) weight of 45 ± 5 kg were intubated and rendered hypoxic by ventilating them with a blend of nitrogen and oxygen to achieve subatmospheric concentrations of inspired oxygen ranging from 18 to 10%, resulting in baseline mean Pao₂ range of 65.9 ± 9.7 to 26.6 ± 2.8 mm Hg, respectively. Peritoneal perfusion was performed in eight animals with oxygenated perfluorocarbon and in seven control animals with oxygenated saline solution.

Results

The average increase in Pao₂ with oxygenated perfluorocarbon perfusion, compared to oxygenated saline solution perfusion, ranged from 8.1 to 18.2 mm Hg. A common treatment effect was estimated across all fraction of inspired oxygen (Fio₂) values, representing the average mean difference in oxygen uptake between oxygenated perfluorocarbon and saline solution, irrespective of the level of Fio₂. This average was 12.8 mm Hg (95% confidence interval, 7.4 to 18.2; p < 0.001). The most clinically relevant results occurred at an Fio₂ of 14%, resulting in a baseline mean Pao₂ of 39.4 ± 5.0 mm Hg with oxygenated saline solution perfusion, and a mean Pao₂ of 55.3 ± 7.6 mm Hg with oxygenated perfluorocarbon perfusion. This corresponded to an increase in arterial oxygen saturation from 73 to 89%.

Conclusion

These results of our principle experiments demonstrate that the peritoneal cavity can be used for gas exchange and, in our model, yielded clinically relevant increases in systemic arterial oxygen levels. This technique may have the potential for the supportive care of patients dying from hypoxia in the setting of reversible lung injury.

Extracorporeal life support for severe acute respiratory distress syndrome in adults

OBJECTIVE

Severe acute respiratory distress syndrome (ARDS) is associated with a high level of mortality. Extracorporeal life support (ECLS) during severe ARDS maintains oxygen and carbon dioxide gas exchange while providing an optimal environment for recovery of pulmonary function. Since 1989, we have used a protocol-driven algorithm for treatment of severe ARDS, which includes the use of ECLS when standard therapy fails. The objective of this study was to evaluate our experience with ECLS in adult patients with severe ARDS with respect to mortality and morbidity.

METHODS

We reviewed our complete experience with ELCS in adults from January 1, 1989, through December 31, 2003. Severe ARDS was defined as acute onset pulmonary failure, with bilateral infiltrates on chest x-ray, and PaO2/fraction of inspired oxygen (FiO2) ratio < or =100 or A-aDO2 >600 mm Hg despite maximal ventilator settings. The indication for ECLS was acute severe ARDS unresponsive to optimal conventional treatment. The technique of ECLS included veno-venous or veno-arterial vascular access, lung "rest" at low FiO2 and inspiratory pressure, minimal anticoagulation, and optimization of systemic oxygen delivery.

RESULTS

During the study period, ECLS was used for 405 adult patients age 17 or older. Of these 405 patients, 255 were placed on ECLS for severe ARDS refractory to all other treatment. Sixty-seven percent were weaned off ECLS, and 52% survived to hospital discharge. Multivariate logistic regression analysis identified the following pre-ELCS variables as significant independent predictors of survival: (1) age (P = 0.01); (2) gender (P = 0.048); (3) pH < or =7.10 (P = 0.01); (4) PaO2/FiO2 ratio (P = 0.03); and (5) days of mechanical ventilation (P < 0.001). None of the patients who survived required permanent mechanical ventilation or supplemental oxygen therapy.

CONCLUSION

Extracorporeal life support for severe ARDS in adults is a successful therapeutic option in those patients who do not respond to conventional mechanical ventilator strategies.

Artificial lungs: a new inspiration

An estimated 16 million Americans are afflicted with some degree of chronic obstructive pulmonary disease (COPD), accounting for 100,000 deaths per year. The only current treatment for chronic irreversible pulmonary failure is lung transplantation. Since the widespread success of single and double lung transplantation in the early 1990s, demand for donor lungs has steadily outgrown the supply. Unlike dialysis, which functions as a bridge to renal transplantation, or a ventricular assist device (VAD), which serves as a bridge to cardiac transplantation, no suitable bridge to lung transplantation exists. The current methods for supporting patients with lung disease, however, are not adequate or efficient enough to act as a bridge to transplantation. Although occasionally successful as a bridge to transplant, ECMO requires multiple transfusions and is complex, labor-intensive, time-limited, costly, non-ambulatory and prone to infection. Intravenacaval devices, such as the intravascular oxygenator (IVOX) and the intravenous membrane oxygenator (IMO), are surface area limited and currently provide inadequate gas exchange to function as a bridge-to-recovery or transplant. A successful artificial lung could realize a substantial clinical impact as a bridge to lung transplantation, a support device immediately post-lung transplant, and as rescue and/or supplement to mechanical ventilation during the treatment of severe respiratory failure.

Extracorporeal membrane oxygenation for severe respiratory failure

The use of extracorporeal technology to accomplish gas exchange with or without cardiac support is based on the premise that "lung rest" facilitates repair and avoids the baso- or volutrauma of mechanical ventilator management. Extracorporeal membrane oxygenation (ECMO), a modified form of cardiopulmonary bypass, has been shown to decrease mortality of neonatal, pediatric and adult respiratory failure and is capable of total gas exchange. In neonates, over 20,638 patients have been treated with an overall survival of 77% in a population thought to have 78% mortality.

Nitric oxide releasing silicone rubbers with improved blood compatibility: preparation, characterization, and in vivo evaluation

Nitric oxide (NO) releasing silicone rubbers (SR) are prepared via a three-step reaction scheme. A diamino triaminoalkyltrimethoxysilane crosslinker is used to vulcanize hydroxyl terminated polydimethylsiloxane (PDMS) in the presence of ambient moisture and a dibutyltin dilaurate catalyst so that the respective diamine triamine groups are covalently linked to the cured SR structure. These amine sites are then diazeniumdiolated, in situ, when the cured SR is reacted with NO at elevated pressure (80 psi). Although nitrite species are also formed during the NO addition reaction, in most cases the diazeniumdiolated polymer is the major product within the final SR matrix. Temperature appears to be the major driving force for the dissociation of the attached diazeniumdiolate moieties, whereas the presence of bulk water bathing the SR materials has only minimal effect on the observed NO release rate owing to the low water uptake of the SR matrices. The resulting SR films/coatings release NO at ambient or physiological temperature for up to 20 d with average fluxes of at least 4 x 10(10) mol x cm(-2) x min(-1) (coating thickness > or = 600 microm) over first 4 h, comparable to the NO fluxes observed from stimulated human endothelial cells. The NO loading and concomitant NO release flux of the SR material are readily adjustable by altering the diamine triamine loading and film/coating thickness. The new NO releasing SR materials are shown to exhibit improved thromboresistance in vivo, as demonstrated via reduced platelet activation on the surface of these polymers when used to coat the inner walls of SR tubings employed for extracorporeal circulation in a rabbit model.

Cerebral tissue oxygen saturation during percutaneous cardiopulmonary support in a canine model of respiratory failure

Percutaneous cardiopulmonary support (PCPS) has come to be applied for cardiopulmonary resuscitation and in the management of severe respiratory failure as well as severe heart failure. We investigated cerebral tissue oxygen saturation during PCPS in a canine model of respiratory failure using near-infrared spectroscopy. Animals were mechanically ventilated with 10% oxygen to make a respiratory failure model. Perfusion with PCPS was performed via the left femoral artery and switched to that via the right axillary artery. Cerebral tissue oxygen saturation was 54.2 +/- 3.4% during PCPS via the femoral artery and was 82.3 +/- 4.6% during PCPS via the axillary artery (p = 0.001). Hepatic tissue oxygen saturation was not significantly different. LV dP/dt max increased significantly after switching to the axillary blood supply (p = 0.001). Conventional PCPS may not have the capability of supporting cerebral circulation under severe respiratory failure without organic heart disease.